How Is Mesothelioma Diagnosed?
Mesothelioma is a type of cancer that affects the linings of the chest cavity or abdominal cavity. Like other types of cancers, it can develop for months of years before it begins to show symptoms. Also like other cancers, it cannot be diagnosed by symptoms alone. Many mesothelioma symptoms are nonspecific, which means that they could indicate mesothelioma or any of many other medical conditions. Some common early symptoms of mesothelioma are cough, fatigue, and shortness of breath, but these could also be symptoms of many other illnesses, including but not limited to lung cancer, emphysema, and COVID-19. Because the symptoms could indicate so many different diseases, most people are very surprised to find out that they have mesothelioma. This is especially the case for people who do not fit the well-known image of mesothelioma patients. The biggest risk factor for mesothelioma is environmental exposure to asbestos dust, so a lot of people associated mesothelioma with elderly men who worked in industries like mining, shipbuilding, and construction in or before the 1980s, before laws went into effect that restrict the use of asbestos-containing materials and require better protective gear whose jobs require them to handle asbestos or be near asbestos dust. Because mesothelioma symptoms usually develop decades after the asbestos exposure occurs, most cases of mesothelioma are in patients above the age of 50, but anyone can get mesothelioma, even people born after 1980 who have never worked with asbestos. Because a definitive diagnosis of mesothelioma requires biopsies of suspected cancerous tissue, and because doctors must perform some preliminary investigations before ordering these tests, it is very unlikely that you will go to the doctor because you have had a cough for weeks and find out at the first visit that you have mesothelioma. Instead, you will have to go through a series of tests over the course of several visits.
A Thorough Medical History
Taking a patient’s medical history is an important part of most medical appointments. The doctor will ask you a lot of questions, only some of which obviously seem related to your health. What does the house you lived in as a child have to do with the persistent cough that you are experiencing in middle age? Why does it matter what your father’s occupation was if he passed away decades ago? These are some aspects of the medical history interview that could be especially relevant when a doctor is trying to decide whether to pursue further tests for mesothelioma:
- Whether anyone in your family has had cancer and how old they were when they were diagnosed
- Whether you have ever smoked tobacco or cannabis and if you have ever lived in the same household as a smoker
- Jobs that you have worked and the occupations of people in your current household or previous households where you lived
- If you have ever lived in a house that was built before the 1980s, a detailed description of that house
Almost everyone who develops mesothelioma has experienced asbestos exposure, but not everyone who has lived or worked in the presence of asbestos fibers will develop mesothelioma. Consider that asbestos was everywhere in the 1950s and 1960s, but you probably had a family member who lived to a ripe old age and never got mesothelioma. If you think that you have mesothelioma risk factors (such as having previously lived with a housemate whose job was to renovate old buildings), you should mention it even if the doctor does not ask about it.
A chest X-ray can show abnormal growths in the lungs or elsewhere in the chest and can be helpful in ruling out certain diagnoses or indicating that you need certain other tests. Most cases of mesothelioma begin with the growth of cancerous cells on the pleurae, which are the linings that cover the chest wall and the outside of the lungs. A chest X-ray can show that there is something abnormal on your lungs or chest wall, but it cannot tell you whether that something is a cancerous tumor or what kind of cancer cells they are. The chest X-ray also shows where the abnormal growth is. If it is inside the lung, the doctor might suspect lung cancer, and if it is concentrated in the lymph nodes of the chest, the doctor might suspect Hodgkin’s lymphoma. Of course, the most dangerous thing about cancers is that they can spread from one part of the body to the other. Some people get a chest X-ray when they go to the doctor complaining of tiredness and shortness of breath, only to find that they have advanced cancer that has spread to the chest from another part of the body, such as the liver. With mesothelioma as with any other cancer, early diagnosis increases the chances of successful treatment and increases the number of years of good health you will be able to enjoy.
If your chest X-ray shows anything unusual, the doctor will order more tests. The chest X-ray might also show a buildup up fluid in the chest; this can be caused by mesothelioma or by any of a wide variety of other conditions. The doctor may want to test the fluid to see if it contains cancerous cells. The doctor might also drain the fluid, which will almost instantly improve your ability to take deep breaths.
Needle Aspirations of Fluid
If your chest X-ray shows that there is fluid in your chest cavity, the doctor will remove a small amount of it with a needle; this is called needle aspiration. Then the doctor will send the fluid sample to a lab to be analyzed. Some people with mesothelioma have cancerous cells in the fluid that have built up in their chest or abdominal cavity. Likewise, if the doctor does an abdominal X-ray and notices that there is fluid buildup in your abdomen, they will do a needle aspiration of this fluid. If the fluid aspirated from your chest or abdomen does not contain cancerous cells, this is good news, but it does not definitely mean that you do not have mesothelioma; it only means that, if you have mesothelioma, it does not spread. Likewise, if the fluid does contain cancer cells, this by itself is not enough to enable the doctor to make a diagnosis specific enough that they can decide on a course of treatment. In either case, you will need a tissue biopsy. This is the only way that the doctor can be completely sure that the abnormal findings on your chest X-ray are mesothelioma and can begin to treat them.
It is not possible to make a definitive diagnosis of mesothelioma without doing a tissue biopsy. In a biopsy, the doctor removes a small amount of tissue from the abnormal growth on your chest wall or wherever the chest X-ray indicated that the abnormal cells were located. This can usually be accomplished through a minimally invasive surgery called a thoracoscopy. If the abnormal growth is located in a part of the chest cavity that is not accessible through a thoracoscopy, then the biopsy will need to be done through open surgery. Growths located in the abdomen can have tissue extracted for biopsy through a minimally invasive surgery called laparoscopy. In any case, the extraction of tissue for biopsy requires you to be under anesthesia, so it will take place at a hospital or outpatient surgery center. After a pathologist examines the tissue samples under the microscope, your doctor can know whether the growths contain mesothelioma cells.
Can Blood Tests Help Diagnose Mesothelioma?
There is no blood test that, by itself, can enable your doctor to make a diagnosis of mesothelioma. Your doctor might order blood tests in addition to X-rays and tissue biopsies, however. Some blood tests measure tumor markers that can corroborate the results of the biopsy regarding what kind of cancer is present. For example, if you have epithelioid mesothelioma, your blood work will show high levels of calretinin, but sarcomatous mesothelioma will not yield this blood test result.
Likewise, before and during your treatment, your doctor will perform blood tests frequently to measure your red blood cell and white blood cell count. A low red blood cell count, known as anemia, and a low white blood cell count, which indicated a weakened immune system, are common in cancer patients, especially those undergoing chemotherapy or radiation treatment. Managing anemia and immune suppression is part of the treatment plan for many cancer patients.
What Happens After a Doctor Makes a Diagnosis of Mesothelioma?
After you have received a diagnosis of mesothelioma, the doctor may perform more tests to see whether cancer has spread, and to what areas of the body, and then decide on a treatment plan. Every mesothelioma patient’s treatment plan is unique. The doctor may perform surgery to remove the tumor, followed by radiation to remove the cancerous cells that surgery could not remove. The mesothelioma treatment that improves survival rates the most, however, is chemotherapy, in which the cancerous growths are exposed to drugs that destroy them. More recently, doctors have also started using immunotherapy drugs like nivolumab and ipilimumab to treat mesothelioma.